The Immunohistochemical Imaging, Flow Cytometry, and Virus Preparation Core is designed to provide technical expertise and services relating to determining the phenotype and distribution of cells within the central nervous system as well as to provide virus stocks for members of the Program Project Grant (PPG). The overall goal of the PPG is to elucidate the cellular and molecular mechanisms of induction and progression of Theiler's virus-induced demyelinating disease. A critical feature is the ability to determine the phenotype of CNS-infiltrating cells as well as their spatial distribution during the development and progression of disease. Furthermore, investigations into disease regulation requires knowledge of how various treatments affect the normal cellular migration and accumulation patterns. This Core will perform three vital functions for the execution of the PPG as a cohesive unit: Aim 1 - immunohistochemical analysis and imaging of CNS and peripheral lymphoid tissues. Aim 2 - Oversight and management of the flow cytometry instrumentation.